1. Field of the Invention
The present invention relates to fabric conditioning articles for washing machines, and more particularly to rinse-released fabric conditioning articles and centrifugally-actuated additive dispensers therefor.
2. Description of Related Art
Paralleling the quest for improved efficacy of laundry products is the quest for improved convenience of use of such products. One approach to the latter is the multi-use approach wherein two or more laundry additives are included on a single delivery substrate. As used herein, "laundry additive" refers to any composition added to enhance the cleanliness, sanitation or aesthetics of fabrics, and includes, but is not limited to detergents, whiteners, fabric softeners, antistat agents, bleaches, bleach activators, anti-redeposition agents, enzymes and mixtures of the foregoing. The multi-use approach contemplates depositing two or more additives targeted at different phases of a laundry cycle, e.g. detergent plus a fabric softener,.upon or within a delivery substrate. The substrate is added to the washer at the start of the laundry cycle, and is designed to dispense the additive at the stage of the laundry cycle where the additive is most effective. Also as used herein, "laundry cycle" refers to the overall laundering process including washing and drying. "Wash cycle" will be used to specifically refer to the phase of the laundry cycle which occurs in the washing machine, and comprises at least a wash phase, a rinse phase and a spin phase. There are several drawbacks associated with multi-use compositions of the art. Typically, delivery of each additive does not occur exactly at the stage of the laundry cycle where its use is most efficient. Multi-use packages are often inefficient owing to their fixed proportions of the various additives. The consumer thus cannot vary the amount of a particular additive without altering the amount of the remaining additives In many cases, delivery of a particular additive does not occur, or incompletely occurs, when intended. This severely reduces performance of the additive. Some additives can interact with their co-additives, also severely reducing their performance. Most multi-use additives include the additive, e.g. fabric softener, with the detergent composition, and such detergents usually hamper the performance of such softeners The detergent/softener compositions are thus relatively easy to use, but do not work well.
Another approach to obtaining the convenience of multi-use with the effectiveness and flexibility of single-use additives is to provide a means for dispensing the additive at the desired points in the laundry cycle. Typically however, such a dispenser is a mechanical device built into the washing machine, and has a limited capability for dispensing additives. Many of these dispensers are suited to dispense only liquid additives and usually are manufactured by the appliance manufacturer to fit only certain washing machines also manufactured thereby. A number of patent references describe dispensers which use centrifugal force developed by a washing machine during a spin phase to effect release of an additive which is most efficacious in the rinse. The centrifugal dispensers of the art described in such references appear to fall into two categories: (a) passive dispensers with no moving parts which rely entirely on centrifugal force to release the additive; and (b), active dispensers which utilize centrifugal force to effect a change in configuration of the dispenser, causing the release of the additive.
Generally, the prior art dispensers of the first type are suited to dispense only liquid additives, which are effective only if delivered in the rinse. The second class of prior art dispensers are often complex, and/or are limited in their application to a small number of washing machine agitators The liquid additives suffer the disadvantage of being inconvenient, and often messy to use, while the mechanical dispensers necessary to dispense the liquid additive generally must be provided by the manufacturer with the washing machine, and cannot be retrofitted.
The first category of prior art dispensers describe, in general, a two-chamber dispenser which is mounted on top of an agitator. An inner chamber has outwardly sloping walls and is initially filled with the additive. Coaxial with and having larger diameter than this inner chamber is an outer chamber with straight walls and often a circumferential channel At the bottom of the second chamber are one or more apertures which allow the additive to drain into the tub of the washing machine. This type of dispenser is utilized by adding liquid additive to the inner chamber During the spin phase, centrifugal force causes the additive to flow out over the sloping walls and into the second chamber, where it continues to flow under the influence of centrifugal force into the circumferential channel. When the spin phase ends, the additive flows by gravity out of the apertures at the bottom of the second chamber and into the tub as it is filling with rinse water. Dispensers of this type are disclosed, for example, by U.S. Pat. Nos. 4,240,277 issued to Manthei; 4,186,574 issued to Sundstrom; 4,118,957 issued to Marcussen; 3,736,773, and 3,699,785 both issued to Waugh; 3,620,054 issued to Drews et al; 3,596,480 and 3,330,135 issued to Douglas; 3,481,163 issued to Bochan et al; and 4,478,059 issued to Yates. It is noted that the foregoing contemplate use with a liquid additive.
Other dispensers which utilize centrifugal force to release an additive, but which are not attached to the agitator include U.S. Pat. No. 4,379,515 issued to Towsend, which describes a free body dispenser having a balloon-like additive reservoir which releases additive under pressure generated by spin phase centrifugal forces, especially if the reservoir is sandwiched between a laundry load and the sidewall of the machine. Brenner et al, U.S. Pat. No. 4,186,573 describes a centrifugally-actuated two-chamber dispenser which hangs on the rim of the wash tub. Operation of the device of Brenner et al is similar to the agitator-mounted two-chamber dispensers, i.e., centrifugal fill of an outer chamber and gravity flow after the spin ceases.
There are numerous prior art dispensers which utilize the centrifugal force generated by the spin to effect a mechanical change in the dispenser and indirectly cause the dispensing of the additive. Clearman et al, U.S. Pat. No. 4,420,951 utilizes a dispenser apparatus mounted on an agitator which also includes a water pump and a nozzle. Under centrifugal force created by the spin, the nozzle is redirected to aim a flow of water into a portion of the dispenser containing the additives. Dugger et al, U.S. Pat. No. 4,026,131 describes a pouch containing an additive and constructed such that a seal on the pouch is broken under the centrifugal force of the spin, freeing the additive. Olthuis, U.S. Pat. No. 3,757,544 shows an agitator mounted dispenser which is held above the water level during the wash. During the spin phase the centrifugal force releases a catch on the dispenser causing it to fall below the rinse water level. McCarthy, T993,001 (US Defensive Publication) describes a spin actuated dispenser having a mass attached to a valve. Bory et al, U.S. Pat. No. 4,260,054 discloses nonsoluble sheets having partially serrated phases which rupture under spin-generated centrifugal force, releasing an additive. Merz, U.S. Pat. No. 3,888,391 discloses a dispenser which releases additive via a centrifugally actuated valve. U.S. Pat. No. 3,670,530, issued to Filipak, shows a dispenser which may be attached to the agitator and comprises a pivotable cup which pivots from vertical to horizontal during spin, pouring out the additive.
In view of the prior art, there remains a need for a mechanically simple dispenser and wash additive combination which can be used with a wide variety of commercially available washing machine agitators, and which is capable of dispensing an effective rinse-added wash additive.
It is therefore an object of the present invention to provide a centrifugally-released substrate which is added at the start of a wash cycle and is specifically adapted for release of actives into the rinse water and/or into the dryer.
It is another object of the present invention to provide a wash-added substrate capable of releasing an active having efficacy in both the rinse and in a dryer.
It is another object of the present invention to provide a wash added substrate capable of releasing a first active into the rinse and a second active into a dryer during a laundry cycle.
It is another object of the present invention to provide a wash additive combination including a dispenser and mounting means therefor adapted for use with virtually any vertical-agitator washing machine.
It is another object of the present invention to provide a means for delivery of laundry additives to a clothes washing apparatus, which means may be added prior to initiating a wash cycle and which will deliver the wash additives during a later, e.g. rinse, phase of a wash cycle.
It is a further object of the present invention to deliver a laundry additive having superior convenience and performance than those of the art.